Hitman series (Link: http://www.jesperkyd.com/ Can't give you a direct link, this is as far as I can get you. But his compositons from the Hitman series and Freedom Fighters are really worth checking out)

Thats about those I can think of right now, I will properbly add more to this post when I think of them. Among my favorites are Jesper Kyd and Bill Brown. Truly brilliant game music artists